Developmental Toxicity of N-Methylformamide Administered by Gavage to CD Rats and New Zealand White Rabbits

N-Methylformamide (NMF) is a metabolite of dimethylformamide(DMF), a solvent with wide applications in the chemical industry.The potential developmental toxicity of NMF was evaluated inCD rats and New Zealand white rabbits. Pregnant rats and rabbitswere dosed once daily by gavage on Gestation Days 6–15and 6–18, respectively. Doses for rats were 0, 1, 5, 10,or 75 mg/kg; doses for rabbits were 0, 5, 10, or 50 mg/kg. Cesareansections were performed on rats and rabbits on Gestation Days20 and 29, respectively. No treatment-related maternal deathsor clinical signs occurred in either species. Body weight gainand food consumption were depressed in rats given 75 mg/kg andrabbits given 50 mg/kg. Fetal viability was reduced at 75 mg/kgin rats and at 50 mg/kg in rabbits. In rats, a significant increasein the incidence of malformations including cephalocele andstern-oschisis was observed in fetuses from the 75 mg/kg group.In addition, a developmental delay was indicated by reductionof fetal weight and by a significant increase in the occurrenceof incomplete ossification of various skeletal structures. Inthe rabbit, fetal body weight was reduced at 50 mg/kg. Malformationsobserved at 50 mg/kg included gastroschisis, cephalocele, domedhead, flexed paw, and skull and sternum anomalies. The lowest-observed-adverse-effectlevels for maternal and developmental toxicity in the rat andrabbit were 75 and 50 mg/kg, respectively. The no-observed-adverse-effectlevel for maternal and developmental toxicity in the rat andrabbit was 10 mg/kg.     

Genetic control of immunity to Heligmosomoides polygyrus: fixed H-2 E positive but not H-2 negative cells can present antigen to a parasite-specific T cell hybridoma

A number of T cell hybridomas were produced to adult worm homogenate (AWH) antigen of the nematode parasite Heligmosomoides polygyrus. All of the hybridomas were of the H-2^d haplotype and could potentially accept antigen in the context of either the A^d or E^d, H-2 molecules. Three types of antigen presentation were observed, with some of the T cell hybridomas accepting antigen in the context of the E and some in the context of the A molecule. A third type of hybridoma responded to antigen presented by paraformaldehyde fixed APC, but only when APCs were Epositive. These same hybridomas, were however, stimulated by A WH, when the antigen was presented by syngeneic but unfixed, E positive or E negative A PC. Therefore these data indicate that certain H. polygyrus-specfic T cell hybridomas can accept parasite antigen when presented in the context of either the H-2 A or E molecule, but the presentation of antigen by the two different MHC Class II molecules, can apparently utilize differing processing mechanisms.,     

The mediating effect of burnout on the relationship between structural empowerment and organizational citizenship behaviours

gilbert s. , laschinger h.k.s. & leiter m (2010) Journal of Nursing Management 18, 339–348
The mediating effect of burnout on the relationship between structural empowerment and organizational citizenship behaviours Aim We used Kanter’s (1977) structural empowerment theory to examine the influence of structural empowerment and emotional exhaustion on healthcare professionals’ use of organizational citizenship behaviours directed at the organization (OCBO) and peers (OCBI). Background Organizational citizenship behaviours (OCB) are discretionary behaviours that are not rewarded directly by the organization but have been linked to positive outcomes, such as increased job satisfaction and lower turnover intentions. Promoting OCB can help employees and organizations flourish despite current challenges in the healthcare system. Structural empowerment may influence the frequency and type of OCB by reducing burnout. Method We conducted multiple mediated regression analyses to test two hypothesized models about relationships between empowerment, emotional exhaustion and two types of OCB (OCBI and OCBO) in a sample of 897 healthcare professionals in five Canadian hospitals. Results Emotional exhaustion was found to be a significant mediator of the relationship between empowerment and OCBO. The predicted mediation of the empowerment/OCBI relationship by emotional exhaustion was not supported. Conclusions Exhaustion was an important mediator of empowering working conditions and OCBO, but was not significantly related to OCBI. Empowerment was significantly related to both OCBO and OCBI. Implications for nursing management Promoting empowerment among healthcare workers may decrease burnout and promote OCB. Specific managerial strategies are discussed in the present study.     

Genetic control of immunity to Heligmosomoides polygyrus: presentation of promiscuous antigens to parasite-specific T cell hybridomas

The role of MHC class II in the presentation of Heligmosomoides polygyrus antigens has been investigated, using a number of T cell hybridomas produced in A and E positive and negative mice. By using fixed and irradiated antigen presenting cells (APC), further evidence has emerged, to support earlier data, that there can be differential processing requirements during the presentation of H. polygyrus antigens by A and E molecules. In concordance with these earlier observations, this work provides further evidence that individual T cells can respond to antigen when presented by more than one MHC molecule. Previously, this evidence has been restricted to individual MHC molecules of the same haplotype, hut these data show that H. polygyrus produces antigens which can he presented by both syngeneic and allogeneic MHC molecules. These antigens do not appear to be synonymous with the previously described H. polygyrus superantigen, as presentation is restricted to specific MHC haplotypes. It is proposed that H. polygyrus may produce these antigenic molecules as part of its strategy to manipulate the host immune system.     

Ventricular fibrillation in an ex‐premature neonate following reperfusion of ischemic gut incarcerated within an inguinal hernia

We describe the case of a neonate who underwent surgery for bowel obstruction. The child was born at 25 weeks postconception, and at the time of surgery, he had a postconceptual age of 44 weeks. He had undergone two previous laparotomy procedures for necrotizing enterocolitis. At laparotomy, there was unexpected extensive compromise to gut perfusion. The child developed ventricular fibrillation following the reperfusion of a segment of ischemic gut found incarcerated in an inguinal hernial orifice. We discuss the pathophysiology of intestinal ischemia–reperfusion (I‐R) injury. We have reviewed the interventions that may be employed to minimize the systemic impact of I‐R.     

Does Atrial Fibrillation Beget Ventricular Fibrillation in Patients with Acute Myocardial Infarction?

Background: Atrial fibrillation (AF) is associated with increased mortality and a higher complication rate postmyocardial infarction (MI), but the exact mechanisms are unknown. We investigated whether AF predisposes to ventricular arrhythmia in postmyocardial infarct patients, thereby accounting for increased mortality. Methods: Five hundred consecutive patients admitted to our coronary care unit with acute MI were monitored for in‐hospital arrhythmias. Detailed information was also compiled on past history, co‐morbidities, electrolyte disturbances, drug therapies, and ejection fraction. Mortality data were collected for an average of 5.5 years. Results: The results have shown that the incidence of ventricular fibrillation (VF) is much greater in patients presenting with AF (P = 0.03) and multivariate analysis has shown that AF is independently associated with the development of VF. This association occurs principally in patients who are admitted with AF (P = 0.01) rather than those who develop it during their admission, although these patients are also at mildly increased risk. The increased incidence of VF does account for increased mortality in the AF patients but does not explain all of their excess risk. There was no association between AF and ventricular tachycardia (VT); P = 0.50. Conclusions: In conclusion, AF on admission to the hospital with acute MI is associated with an increased risk of VF and subsequent mortality.     

A randomized trial comparing sevoflurane and propofol in children undergoing MRI scans

Objectives:  We compared three primary outcomes of pausing the magnetic resonance imaging (MRI) scan, emergence quality and respiratory complications.
Aim:  To measure and compare the quality between sevoflurane and propofol in children undergoing MRI scans.
Background:  No randomized controlled trial exists comparing the quality between sevoflurane and propofol for MRI.
Methods/Materials:  Two hundred unpremedicated children (18 months to 7 years) scheduled for brain MRI scans were recruited. After induction with sevoflurane, children were randomized to receive sevoflurane [general anesthesia with sevoflurane (GAS)] via laryngeal mask airway (LMA) or propofol [general anesthesia with propofol (GAP)] bolus and infusion for their scan. The three primary outcomes of pausing the MRI scan (P), agitation (A), and respiratory complications (R) were compared. Timeliness of care was also measured.
Results:  No MRI scan pauses were found in 92% and 80% in the GAS and GAP groups. The median and interquartile A scores were 3 (0, 7) in GAS and 0 (0, 4) in GAP groups respectively. There was no difference in respiratory complications between GAS and GAP ( P  = 0.62). The median and interquartile postanesthesia care unit (PACU) times were 25 (18, 34) for GAS and 31 (25, 44) for GAP ( P  = 0.0001). The median and interquartile total times were 78 (69, 90) for GAS and 88 (78, 100) for GAP ( P  = 0.0002).
Conclusion:  Our study compared the three primary outcomes of pausing, agitation, and respiratory complications between the two groups, and we found no difference in respiratory complications. However, the GAP group had more pausing and less agitation than the GAS group.     

An in Vitro Comparison of Rat and Chicken Brain Neurotoxic Esterase

An in Vitro Comparison of Rat and Chicken Brain Neurotoxic Esterase.NOVAK, R., AND PADLLA, S. (1986). Fundam. Appl. Toxicol. 6,464–471. A systematic comparison was undertaken to characterizeneurotoxic esterase (NTE) from rat and chicken brain in termsof inhibitor sensitivities, pH optima, and molecular weights.Paraoxon titration of phenyl valerate (PV)-hydrolyzing carboxylesterasesshowed that rat esterases were more sensitive than chicken toparaoxon inhibition at concentrations <1 µM and superimposablewith chicken esterases at concentrations of 2.5–1000 µM.Mipafox titration of the paraoxon-resistant esterases at a fixedparaoxon concentration of 100 µM (mipafox concentration:0-1000 µM) resulted in a mipafox 150 of 7.3 µM forchicken brain NTE and 11.6 µM for rat brain NTE. NTE (i.e.,paraoxon-resistant, mipafox-sensitive esterase activity) comprised80% of chicken and 60% of rat brain paraoxon-resistant activitywith the specific activity of chicken brain NTE approximatelytwice that of rat brain NTE. The pH maxima for NTE from bothspecies was similar showing broad, slightly alkaline optimafrom pH 7.9 to 8.6. [³H]Diisopropyl phosphorofluoridate (DFP)-labeledNTE from the brains of both species had an apparent mol wt of160,000 measured by sodium dodecyl sulfate polyacrylamide gelelectrophoresis. In conclusion, NTE from both species was verysimilar, with the mipafox 150 for rat NTE within the range ofreported values for chicken and human NTE, and the inhibitorparameters of the chicken NTE assay were applicable for therat NTE assay.     

The effect of area of application on the intensity of response to a cutaneous irritant

The intensity of the cutaneous response was assessed after application of a standard irritant to increasing areas of normal forearm skin. Twenty subjects were tested to determine the minimal irritant dose (MID) to dilutions of aqueous sodium dodecyl sulphate. Each subject was then treated under occlusion for a period of 24 h with different areas of filter paper (9, 25, 100, 225 and 400 mm2) soaked with the concentration required to give the individual's MID. At 25 and 48 h the degree of erythema was assessed using a 0-4 arbitrary scale, a 10-cm visual analogue scale (VAS) and an erythema meter. Cutaneous blood flow was measured with a laser-Doppler device and cutaneous oedema measured by pulsed A-scan ultrasound. The results at 25 and 48 h were almost identical. Both forms of visual assessment (arbitrary scale and VAS) showed an increase in perceived erythema with increasing area and this was confirmed by the erythema meter. Further area-related changes were noted with both cutaneous blood flow and ultrasound measurements.